A resistive type touch panel and a capacitive type touch panel according to the related art may simply recognize only location information of a touch but cannot recognize strength or force of the touch when all screen inputs are achieved. In addition, since a touch panel layer is placed at a top end of a display layer, a structure becomes complicated and the visibility of a display is degraded. Accordingly, researches and studies have been performed toward a touch panel using a piezoelectric element other than an existing scheme.
Since the piezoelectric element has a property capable of converting a mechanical signal such as pressure into an electric signal, the piezoelectric element has been extensively used for a sensor such as a pressure sensor or an ultrasonic sensor.
However, as the electronic appliances have been extensively used, there are various demands of users to use the electronic appliances having various functions. Accordingly, there is a need to maximize user's experience by providing various feedbacks, such as tactile sense feedbacks or partial tactile feedbacks, when touching a touch panel.